That's how they nab ya... they'll send you an amp or two for free and then take your larger order and you get air in return... My suggestion is delete any email from a source who emails you unless it's in reply to something you sent to him.
I get mails all the time. IMO good sources do not have to spam mail to get business they have slowley buit up by reputation. These operate by referal only and are safer for you and them.
IMO just delete Bro the Mods will probably already know of them as they will be being asked to source check them.